1. Field of the Invention
This invention relates to a battery pack connection, and more particularly, a battery pack connection in which a battery pack can be quickly and efficiently replaced upon discharge of the batteries.
2. Description of Prior Art
The present invention has particular utility when used with electrical devices that are portable and which derive their power from batteries that are contained within a pack and which are generally connected by a cable to the device. Typically, the power supplied by the battery pack is utilized quite rapidly requiring frequent replacement of a discharged battery pack by a freshly charged pack. The replacement of a pack has generally required both an operation which effects disconnecting of the electrical connection between the pack and the device and also another operation which separates the pack from its supporting structure so that not only was replacement somewhat time consuming and requiring the user's undivided attention, but also it was susceptible to improper securement and connection.
Therefore, in U.S. Pat. No. 4,218,107, assigned to the same assignee as the present invention, a battery pack connection was disclosed which includes a female plate that is secured, as for example, directly to a portable device or may be carried by the user by being strapped to the user's body. The female plate is formed with a plurality of keyholes together with at least one male terminal with the keyholes and the terminal extending in the same direction but with the terminal being positioned within a recess spaced beneath the plane of the female plate. A male plate cooperates with the female plate and may form one side of a battery containing receptacle or pack or other similar electrical device. The male plate has a plurality of circular headed projections extending therefrom and at least one female terminal positioned within a housing that projects from the plane of the male plate.
In use, the female plate is fixed and connected to the electrical device and if the male plate is part of the battery pack, the user positions the male plate against the female plate with initial alignment occurring between the recess and the housing and with said alignment preventing lateral shifting of the plate with respect to the slots of the keyholes. The user can then only move the male plate in the direction of the keyhole slots until the headed projections enter into circular openings of the keyholes. The male plate is then further moved to position the projections within the slots of the keyholes with said movement causing electrical connection between the male and female terminals.
When the male plate has achieved its connected position, a tensioned flexible strip that is positioned behind one keyhole reverts to its normally biased position wherein it has a ledge which engages the head of the projection in said keyhole and prevents the two plates from moving from their connected position.
For removing the plate, the user merely bends the flexible strip from its normal position which unlocks the engagement between the strip and the projection to thereby permit the male plate to be moved so as to position the headed projections within the circular openings of the keyholes. At this position, the terminals have been disconnected and the male plate can be removed from the female plate in order to permit a charged battery pack to be replaced on the female plate.
The portion of the keyholes in the female plate for receiving the circular headed projections on the male plate are also all circular in shape and of a similar diameter. Thus precise horizontal and vertical alignment of all the projections simultaneously with the respective keyholes is a prerequisite for proper engagement of the two parts. This prealignment process is relatively difficult and has the undesirable effect of impeding the overall speed of engagement. This deign also requires two distinct and perpendicular motions for full engagement; insertion of the projections into the keyholes followed by a lateral motion which make electrical contact and locks the mating parts. This double motion further reduces the overall speed of engagement. Also, in order to remove the male plate from the female plate so as to readily replace the battery pack, it was necessary to hold the flexible strip in its bent position with one hand while removing the male plate with the other, which is somewhat awkward. In addition to requiring two hands, disengagement was further complicated by the requirement of two distinct motions; a lateral movement to electrically disconnect followed by a retraction in a direction perpendicular to the first.
These problems were addressed and rectified in the improved battery pack connection disclosed in U.S. Pat. No. 4,550,968, also assigned to the same assignee as the present invention. The top of each keyhole slot on the female plate, rather than being closed and/or circular, is rectangular and elongated in the direction of the slot. Where possible, for example, in those slots adjacent the top or side edge, the slots open into the edge enabling the corresponding headed projections on the male plate to be quickly located in the slots. The remaining interior slot or slots are provided with an inclined ramp to guide a mating headed projection on the male plate quickly into locking engagement with the bottom of the slot and as a consequence causes the remaining headed projections to seek their locked positions. Thus, alignment prior to engagement is significantly easier requiring positioning of only one projection instead of a plurality and in one plane instead of two. Engagement is further expedited by a one motion process instead of two.
The flexible locking strip was also provided with a latch actuator having a cam for contact with the flexible strip so that the flexible strip can be moved away from its normally biased position enabling the headed projections to be removed from the keyhole slot. In this position, the latch actuator cam projects into the keyhole slot in front of the flexible strip wherein upward movement of the male plate and headed projection will return the latch actuator to a position out of contact with the flexible strip, permitting the same to be resiliently bowed to clamp a headed projection when placed in the keyhole slot. Movement of the latch actuator from this position towards the strip causes the cam to raise the strip and remain in a raised position, wherein the male plate can be removed from the keyhole slots with the same hand. Alternatively, in the event the latch actuator has not been returned to a position out of contact with the flexible strip, the latch actuator is provided with a second cam having a camming surface which will contact a downwardly moving headed projection inserted in the keyhole slot to move the latch actuator to its first position out of contact with the flexible strip. Once again, mating relation of the plates can be accomplished with one hand. This convenience is further enhanced by a one motion removal rather than the previous two motion and direction removal process.
While the foregoing generally proved satisfactory in use, the present invention is direction to further improving several features of the battery pack connection.
First, inadvertent contact with the latch actuator could cause it to move towards the flexible locking strip to cam the strip to a held raised position, enabling the male plate to be unintentionally dislodged from the female plate. In order to prevent this from occurring, the locking mechanism should be provided with a positive return to its closed position, once opened, as a safety feature, even if two hands are required to remove the male plate from the female plate, although the subsequent function o being able to insert the male plate into the female plate so as to replace the battery pack with one hand is retained. A safety latch can also be provided to retain the locking mechanism in its closed position.
Bi-directional insertion and removal of the male plate with respect to the female plate has also been found to be more desirable to assure proper mating of the male and female contact terminals and to preclude inadvertent disassociation of the male plate from the female plate upon accidental opening of the locking mechanism. This is accomplished by returning to the use of keyhole slots receiving the headed projections on the male plate, but designing the slots so that the headed projections are more easily aligned with the corresponding slots in the female plate, thereby retaining quickness and ease of assembly and disassembly.
Finally, means are provided to assure proper alignment and entry of the male contact terminals into the female contact terminals upon assembly of the male and female plates along with improved securement means for the headed projections on the surface of the male plate to prevent loss thereof.